JPH0674843B2 - Continuously variable transmission for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a continuously variable transmission device for a vehicle, which is effective during a sudden deceleration shift of a continuously variable transmission, that is, during a sudden acceleration of the vehicle.

2. Description of the Related Art A continuously variable transmission that continuously changes the driving force output from an internal combustion engine can control the operation of the internal combustion engine at the minimum fuel consumption rate over the entire operating range. Application is proposed.

Incidentally, the continuously variable transmission is gear-shift-controlled based on the throttle valve opening, the vehicle speed, and the like. Therefore, for example, when the driver depresses the accelerator pedal with the intention of sudden acceleration, the gear ratio of the continuously variable transmission is increased,
A so-called sudden deceleration shift is performed. In such a case, since the vehicle inertia is large, the output shaft rotation speed of the continuously variable transmission does not suddenly decrease, but remains high. Therefore, the input shaft rotation speed of the continuously variable transmission rapidly increases due to the sudden deceleration shift. When the input shaft rotation speed becomes higher than the rotation speed of the internal combustion engine, the internal combustion engine is driven by the drive transmission system, a so-called engine braking state occurs, and the vehicle receives a braking force temporarily. For this reason, when a vehicle equipped with a continuously variable transmission is used to perform rapid acceleration, a phenomenon occurs in which the vehicle is temporarily decelerated and then transitions to an accelerated state due to the braking force associated with the sudden deceleration shift.

As a countermeasure against such a problem, for example, the main clutch interposed between the internal combustion engine and the continuously variable transmission is slipped or separated during a sudden deceleration shift to suppress the braking force. The technology is known.

[Problems to be Solved by the Invention] The related art described above has the following problems. That is, (1) Even if the main clutch interposed between the internal combustion engine and the continuously variable transmission is slipped during the rapid deceleration shift, the generation of the braking force cannot be completely prevented. . That is, the braking force was generated according to the degree of slippage of the main clutch.

(2) Further, in the case where the main clutch is slipped as in the above (1), there is a problem that deterioration of the main clutch is apt to occur and its reliability and durability are deteriorated.

(3) Further, as a measure against the problem of the above (1), for example, an improved technique of increasing the slip amount of the main clutch or completely separating the main clutch has been considered. However, such improved technology is extremely difficult to achieve the responsiveness and accuracy required in controlling the engagement timing of the main clutch, and is still not sufficient.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vehicle continuously variable transmission that prevents generation of a braking force associated with a sudden deceleration shift during sudden acceleration.

Configuration of the Invention [Means for Solving the Problems] The present invention made to solve the above problems, as illustrated in FIG. 1, continuously changes the driving force output from the internal combustion engine M1. A continuously variable transmission for a vehicle, comprising a connecting portion M3 for connecting and disconnecting the driving force to either the input side or the output side of the driving force of the continuously variable transmission M2 that is transmitted to the driving wheels, The one-way clutch M4, which is connected only when the driving force is transmitted from the internal combustion engine M1 to the drive wheels, is arranged in parallel with the one-way clutch M4, and the connecting portion M3 is normally connected. A continuously variable transmission for a vehicle, which has a clutch M5, and further comprises control means M6 for separating the clutch M5 during a sudden deceleration shift of the continuously variable transmission M2. is there.

The continuously variable transmission M2 can be realized by, for example, a so-called belt type continuously variable transmission in which a belt is placed between an input pulley and an output pulley and the effective diameter of the belt is changed. Also, for example,
It may be a traction drive type continuously variable transmission that uses a traction roller to perform continuously variable transmission.

The clutch M5 can be realized by, for example, a dog clutch that switches between two states of connection and disconnection. Also, for example,
It may be a dry single plate clutch or the like. Further, for example, it may be configured such that it is normally in the connected state by the biasing of the spring force, and shifts to the separated state by the operation of a hydraulic or electromagnetic actuator.

The control means M6 is for separating the clutch during the rapid deceleration shift of the continuously variable transmission. For example, the clutch may be connected after outputting a command to the actuator to disengage the clutch and start the transmission of the driving force of the one-way clutch during the rapid deceleration shift of the continuously variable transmission. The control means M6 can be realized by, for example, a discrete logic circuit. Further, for example, a well-known CPU, ROM, RAM, and other peripheral circuit elements may be configured as a logical operation circuit, and the control means M6 may be realized according to a predetermined processing procedure.

[Operation] In the continuously variable transmission for a vehicle of the present invention, as illustrated in FIG. 1, the control means M6 disengages the clutch M5 of the coupling portion M3 during the rapid deceleration shift of the continuously variable transmission M2, and the internal combustion engine The one-way clutch M4 works to transmit only the driving force from M1 to the driving wheels.

That is, when the rotation speed of the continuously variable transmission M2 is higher than the rotation speed of the internal combustion engine M1 during the rapid deceleration shift, the clutch M5 is disengaged, and therefore the clutch M5 moves from the drive transmission system to the internal combustion engine M1. The driving force is not transmitted due to the action of the one-way clutch M4.

Therefore, the continuously variable transmission for a vehicle of the present invention works to suitably prevent the generation of the braking force that accompanies the sudden deceleration shift of the continuously variable transmission M2. The technical problems of the present invention are solved by the action of each component of the present invention as described above.

[Embodiment] Next, a preferred embodiment of the present invention will be described in detail with reference to the drawings. FIG. 2 shows a system configuration of a continuously variable transmission for a vehicle which is an embodiment of the present invention. Continuously variable transmission 1 for vehicle
Is a drive force of the engine 2 for the main clutch 3, and a one-way clutch 4 and a clutch 5 arranged in parallel behind the main clutch 3.
It is configured to be transmitted to a continuously variable transmission (hereinafter, simply referred to as CVT) 6 via. The main clutch 3 is a magnetic powder type electromagnetic clutch. If the main clutch 3 can be set in a half-clutch state, for example, a centrifugal clutch,
It may be a wet clutch or the like. The main clutch 3 is provided, for example, in order to enable the engine 2 to be in an idle state and to smoothly start the vehicle. One-way clutch 4
Transmits only the driving force from engine 2 to CVT6,
The driving force in the opposite direction to the above is not transmitted. The clutch 5 arranged in parallel with the one-way clutch 4 is composed of a dog clutch, and changes to two states of a connected state and a disengaged state. Normally, the clutch 5 is in the connected state by the bias of the spring 7, and is in the disengaged state by the operation of the hydraulic actuator 8. The driving force input to the CVT 6 is transmitted in the order of the input shaft 10, the input pulley 11, the belt 12, the output pulley 13 and the output shaft 14. The input side pulley 11 and the output side pulley 13 are provided with hydraulic chambers 15 and 16, respectively. Both hydraulic chambers 15 and 16 are pressure-fed by a hydraulic pump 18 from a reservoir 17 and change in volume due to hydraulic oil supplied via a pressure control valve 19 and a flow control valve 20. Each movable pulley slides in its axial direction. Therefore, the effective diameter of the winding position of the belt 12 changes, which enables a stepless speed change operation. The driving force is the output shaft of CVT6.
It is transmitted from 14 to the drive wheels via a reduction gear and a differential gear (not shown).

The vehicle continuously variable transmission 1 includes, as detectors, a throttle position sensor 21 that detects a throttle valve opening of the engine 2, a rotation speed sensor 22 that detects a rotation speed of the engine 2, a vehicle speed sensor 23 that detects a vehicle speed, and an input. An input shaft rotation speed sensor 24 for detecting the rotation speed of the shaft 10 and an output shaft rotation speed sensor 25 for detecting the rotation speed of the output shaft 14 are provided.

A signal from each of the above sensors is input to an electronic control unit (hereinafter simply referred to as an ECU) 30 that functions as control means M6, and the E
The CU 30 drives the pressure control valve 19, the flow rate control valve 20 and the hydraulic actuator 8 to control the vehicular continuously variable transmission 1.

The ECU 30 is configured as a logical operation circuit centering on the CPU 30a, ROM 30b, and RAM 30c, and is connected to the input unit 30e and the output unit 30f via the common bus 30d to perform input / output with the outside.

Next, the clutch control process executed by the ECU 30 will be described based on the flowchart of FIG. The present clutch control processing is started when the vehicle starts and is repeatedly executed at predetermined time intervals. In step 100, it is determined whether or not the flag i is reset to 0. If the determination is affirmative, step 110 is performed. If the determination is negative, step 1 is performed.
Proceed to 40 each. The flag i is set to the value 1 as the clutch 5 is disengaged, and is reset to the value 0 as the clutch 5 is engaged. In step 110 executed when the clutch 5 is engaged, the speed ratio deviation (e-
It is determined whether or not e *) / e is greater than or equal to the separation reference value C1,
When the determination is affirmative, the process proceeds to step 120, and when the determination is negative, the process proceeds to step 150.

Here, the speed ratio e is given by output shaft rotation speed / input shaft rotation speed. The target speed ratio e * is a value calculated by the ratio between the input shaft rotation speed of the CVT 6 determined according to the map according to the throttle valve opening and the output shaft rotation speed of the CVT 6 determined according to the vehicle speed. Speed ratio deviation is separation reference value C1
In step 120 executed when the above is the case, the process of driving the hydraulic actuator 8 to disengage (OFF) the clutch 5 is performed. In the following step 130, the flag i is set to the value 1, and then the present clutch control processing is ended.

On the other hand, in step 140, which is executed when the clutch 5 is disengaged, it is determined whether or not the speed ratio deviation is equal to or less than the connection reference value C2. Then, the process proceeds to step 120 described above. In step 150 executed when the speed ratio deviation is equal to or less than the connection reference value C2, the process of connecting (ON) the clutch 5 is performed. In the following step 160, after the processing of resetting the flag i to the value 0 is performed, the present clutch control processing is once terminated. After that, the present clutch control processing is repeatedly executed as described above.

Through the clutch control process, the clutch 5 is connected or disconnected as shown in FIG. That is, at the time of sudden deceleration shift, the gear ratio e becomes considerably larger than the target speed ratio e *, so the speed ratio deviation increases. Therefore, after the shift is started, the clutch 5 is still engaged (ON) as long as the speed ratio deviation is less than the separation reference value C1 and it is not a rapid deceleration shift. Assumed, the clutch 5 is disengaged (OFF).

On the other hand, the clutch 5 that has been disengaged (OFF) is connected only after the one-way clutch 4 is connected. Therefore, while the speed ratio deviation is larger than the connection reference value C2, the clutch 5 is disengaged (OFF) assuming that the one-way clutch 4 is not connected yet, and the one-way clutch is immediately before the end of the shift when the connection reference value C2 or less is reached. Assuming that 4 is connected, the clutch 5 is connected (ON). As described above, the separation reference value C1 is set to a large value on the premise of a sudden deceleration shift, while the connection reference value C2 is set to a small value on the premise that the one-way clutch 4 is connected.

As described above, in the present embodiment, when the speed ratio deviation becomes equal to or greater than the separation reference value C1, the clutch 5 is separated and the engine 2 is separated.
CVT6 is connected only by one-way clutch 4, while clutch 5 is engaged when the speed ratio deviation becomes less than the connection reference value C2.
Are configured to connect. Therefore, even when the rotation speed of the input shaft 10 of the CVT 6 exceeds the rotation speed of the engine 2 during the rapid deceleration shift of the continuously variable transmission 6, the one-way clutch 4 acts to reversely transfer the driving force from the input shaft 10 to the engine 2. Does not occur. Therefore, it is possible to prevent the generation of braking force and improve the so-called drive feeling such as acceleration performance and riding comfort.

That is, since the one-way clutch 4 has not been interposed in the past, as shown in FIG. 5 (1), the engine speed Ne during the sudden deceleration shift and the rotation speed Nin of the input shaft 10 of the CVT 6 are the same. there were. Therefore, the reverse transmission of the driving force (negative transmission driving force) is performed from the CVT 6 to the engine 2 from time T1 to T2, and a braking force such as a so-called engine braking phenomenon is generated. However, if the one-way clutch 4 that transmits the driving force only in the direction from the engine 2 to the CVT 6 is provided as in this embodiment, as shown in FIG. 5 (2), the engine rotation speed Ne ( During the time T11 to T12 when the rotation speed Nin (broken line) of the input shaft 10 of the CVT 6 exceeds the solid line), the reverse transmission of the driving force (negative transmission driving force) from the CVT 6 to the engine 2 is not performed.
This is because the one-way clutch 4 idles and absorbs the rotational speed difference between the input shaft 10 of the CVT 6 and the engine 2.

Further, in the present embodiment, the simple structure in which the one-way clutch 4 and the clutch 5 are arranged in parallel can prevent a temporary braking force from being generated and enable a quick shift.

Further, in the present embodiment, it is not necessary to slip or disengage the main clutch 3 at the time of sudden deceleration shift of the CVT 6, and only the connection and disengagement control of the clutch 5 having a simple structure that changes to two states is sufficient. Therefore, the control is facilitated, and the reliability and durability of the main clutch 3 are improved.

Further, since the performance required for the main clutch 3 at the time of sudden deceleration shift of the CVT 6 is reduced, the degree of freedom in designing the drive transmission system is increased.

Further, the separation reference value C1 is set to a sufficiently large value, while the connection reference value C2 is set to a sufficiently small value, and the clutch 5 is connected or disconnected by comparing with the speed ratio deviation. For this reason,
Since the clutch 5 is disengaged only during the CVT6 sudden deceleration shift,
During a normal slow deceleration shift, for example, when the vehicle is approaching a steep downhill after a slow deceleration, it is possible to shift to the engine braking state and secure the braking force. On the other hand, since the clutch 5 is connected after the one-way clutch 4 is connected, the engagement shock when the clutch 5 is connected can be prevented.

Further, the clutch 5 is normally in the connected state by the spring 7 and is in the disengaged state only when the hydraulic actuator 8 is operated. Therefore, for example, even if the hydraulic actuator 8 does not operate normally due to an abnormality in the hydraulic system,
The spring 7 allows the clutch 5 to maintain the connected state. Therefore, it has a fail-safe function of ensuring the braking force depending on the engine braking state even when the hydraulic system is abnormal.

Although the clutch 5 is separated by the hydraulic actuator 8 in this embodiment, the clutch 5 may be separated by an responsive actuator such as an electromagnetic actuator.

In this embodiment, the one-way clutch 4 and the clutch 5 are arranged in parallel between the engine 2 and the input shaft 10 of the CVT 6. However, for example, as shown in FIG. 6, the one-way clutch 4 and the clutch 5 may be arranged in parallel between the output shaft 14 of the CVT 6 and a reduction gear (not shown). With this configuration, CVT6
At the time of the sudden deceleration shift, the engine 2 and the CVT 6 can be separated from the drive wheel side. Therefore, it is possible to completely prevent the generation of the braking force acting on the drive wheels due to the inertia of the drive transmission system (for example, the input shaft side of the CVT 6). The control of connection and disconnection of the clutch 5 is the same as that of the above-mentioned embodiment.

Although the embodiments of the present invention have been described below, the present invention is not limited to such embodiments, and it goes without saying that the present invention can be implemented in various modes without departing from the scope of the present invention. .

As described above in detail, in the continuously variable transmission for a vehicle of the present invention, the clutch of the connecting portion is disengaged and the driving force is applied only in the direction from the internal combustion engine to the drive wheels during the rapid deceleration shift of the continuously variable transmission. Is configured to engage only the one-way clutch transmitting. For this reason, since the driving force from the drive transmission system is not transmitted to the internal combustion engine during the rapid deceleration shift of the continuously variable transmission,
It is possible to reliably prevent generation of a braking force due to sudden acceleration, and it is possible to improve the overall performance of the vehicle such as running performance and riding comfort.

In addition, quick gear shifting that prevents the adverse effects of braking force generation can be reliably realized with a simple device configuration.

Furthermore, since it is not necessary to slide the main clutch that connects the internal combustion engine and the drive transmission system at the time of shifting, deterioration of the main clutch can be prevented, and reliability and durability are improved.

Further, at the time of the sudden deceleration shift, it is sufficient to disengage the clutch to which the connecting portion is connected, so that it is possible to prevent the generation of the braking force at the time of the sudden deceleration shift by a simple control.

Furthermore, it is no longer necessary to slip the main clutch or to control the connection and disconnection accurately and responsively during a sudden deceleration shift. Therefore, the required performance of the main clutch is reduced, and the degree of freedom in design is increased with the expansion of the selection range when designing the main clutch.

[Brief description of drawings]

FIG. 1 is a basic configuration diagram conceptually illustrating the content of the present invention, and FIG. 2 is a system configuration diagram of an embodiment of the present invention, and FIG.
FIG. 4 is a flow chart showing the same control, FIG. 4 is an explanatory view showing the speed ratio deviation and the state of the clutch, and FIGS. 5 (1) and 5 (2) are timing charts showing changes in rotational speed and transmission driving force. FIG. 6 is a system configuration diagram showing another embodiment of the present invention. M1 ...... Internal combustion engine M2 ...... Continuously variable transmission M3 ...... Coupling M4 ...... One-way clutch M5 ...... Clutch M6 ...... Control means 1 ...... Vehicle continuously variable transmission 2 ...... Engine 4 ...... One-way clutch 5 …… Clutch 6 …… CVT 8 …… Hydraulic actuator 21 …… Throttle position sensor 24 …… Input shaft rotation speed sensor 25 …… Output shaft rotation speed sensor 30 …… Electronic control unit (ECU) 30a ……CPU

Claims (1)

[Claims] Claim: What is claimed is: 1. A driving force is connected and disconnected to either the input side or the output side of the driving force of an continuously variable transmission that continuously changes the driving force output from an internal combustion engine and transmits it to the driving wheels. A continuously variable transmission for a vehicle having a connecting portion, wherein the connecting portion is connected only when a driving force is transmitted from the internal combustion engine to the drive wheels, and a one-way clutch connected in parallel with the one-way clutch. And a clutch that is normally connected to the continuously variable transmission, and a control unit that separates the clutch during a sudden deceleration shift of the continuously variable transmission. Gearbox.